Problem with PC rebooting

[Dropndestroy213]

Hey guys so the pass week my PC started to reboot randomly. as of 2 weeks ago it got bad i would boot up log in and it will reboot and freeze up. After talking to Asus tech i went and got a new motherboard and a Nvme m.2 ssd got in installed Also replaced the power supply yesterday and it all seem fine ran a stress test for 30mins used the system for about 7 hrs and it was fine. This morning i turn it on go to you tube and it reboots when it  loads back up and  while putting my windows password it reboots again.
I have changed my motherboard and boot drive and power supply. Latest Bios and fresh install of windows.
Any help will be great not sure what happen i built my pc back in March and has been fine until about 2 weeks ago.

Build is
Asus maximus 9 formula
I7 6700k stock
Gskill rgb ram 3200 16gb XMP
Strix 1080
Samsung 960 evo 500gb m.2 nvme ssd
Toshiba ocz 480gb ssd
Crucial mx300 1tb ssd
Seagate BarraCuda 4tb
Evga 850w p2
Thermaletake core p3
Custom cpu and gpu loop

[ImNotThere]

sounding like a psu issue

potentially ram related, try booting with 1 stick of ram

if possible try with a different psu

[Dropndestroy213]

44 minutes ago, ImNotThere said:

sounding like a psu issue

potentially ram related, try booting with 1 stick of ram

if possible try with a different psu

i swapped the psu yesterday with a evga 850 p2 n right now i swapped ram out lets see what happends now 

[Dropndestroy213]

Heys guys so a quick update . Seems like the problem what a bad PCIE Riser cable causeing all the problems.put a new one on Thursday after pretty much only thing left from my original build was the GPU, CPU, and drives